Car starts, revs and dies

[Loewen21]

Ok i know there are several other threads about this as i searched, but none of them are quite the same. Like stated when i start the car it will start and rev to about 3000 then slowly rev down and die. When checking the voltage the injectors are getting it seems to be constant?? and from my understanding it should go on then off correct?? I know its not the ecu as we tried that and it works fine in my friend's car. Could it be the cam angle sensor that could do this?? Or maybe the injector driver box (not sure of the proper name sorry) Any input from wiseman or any knowledgeable source would be great guys. Thanks alot.

 

[TSi_with_psi]

The voltage going to the injecters should be constant. The ECU does not switch on and off the power to the injectors, it controls the ground side of the circuit. You will have a difficult time accuratly testing the fuel injecters with a digital voltmeter since a digital voltmeter takes an average of the voltage it sees, so you will not be able to see a pulsating voltage. On the ground side of the injecters with the car running, the voltmeter will show the average voltage. Since the Injecter Dudy Cycle will be low at idle you should see a voltage under 6volts. It just depends on how quick the voltmeter responds. The best way to test injecters is with an Oscilloscope, but most people dont have access to one. You can also use a test light and hook the test light up to the positive side of the battery. Then touch the test light to the ground side of the injectors. Every time the computer grounds the injector, the test light will flash. Using the test light is the fastest and easiest way to test the injectors.

 

[kenamond]

Could be the CAS. My 2g acted that way when the CAS started dying. Wiggling the CAS connector fixed things temporarily for me. Didn't throw a code right away, but after a few days, it finally did (CAS code...forget what it is). If someone has a 1g CAS like yours (I recall there are different CAS sensors on different 1g years), try swapping it out. Mine would start, rev, die. I could keep it running with the pedal for a few seconds. Black exhaust and fuel stink from the exhaust.

 

[Loewen21]

Ah the site never fails alright well i shall give the CAS a try tonight hopefully then and report back with any results.

 

[Loewen21]

Ok so little update here. We tried a test light on the injectors and seemed to only get a dim light as if it wasn't getting proper voltage. I know for a fact the ecu is good because i tried it in a buddies car yesterday and it worked great. So what could cause this? We were thinking the shot resistors in the injector wiring possibly but input from someone more knowledgeable would be much appreciated.

 

[EDM95]

Maybe you have a defective computer, or information sensor.
Did you check for vacuum leaks?

 

[Loewen21]

Maybe you have a defective computer, or information sensor.
Did you check for vacuum leaks?

I know for a fact that the computer is fine as i just tried it in someone elses car to make sure. Also vacuum leaks are good and what the hell is an information sensor??? BTW i am running a MAP sensor with an HKS VPC instead of the stock MAF.

 

[kenamond]

Have you checked your battery or tried starting it with jumper cables? The ECU gets very flakey if the voltage drops too low. My CAS cost over $80, so I'd see about testing a known good unit before you lay cash down for a part that might not solve your problem.

 

[Spyder4g64]

Has this problem started after the install of the MAP and VPC? It sounds like a metered air problem to me..

 

[Loewen21]

No the map and vpc have been in there for about 2 years now and i tested the map sensor and it came up fine. Well i have a friend that is willing to let me try his CAS so i'll try that.

 

[Loewen21]

Ok so a little update here guys. On a last ditch effort we tried disconnecting the VPC to see if that would make a difference. So we did that and started it and it started up and idled, albeit rough, but it idled. What the hell!! There was on MAP sensor, no MAF no nothing tell the engine how much air was coming in but it still idled. Would this mean the VPC unit itself is shot?? Help guys!